Vibration characteristic analysis of the multi-drilling mechanism

For enhancing drilling efficiency and controlling drilling direction, it is necessary to predict and control dynamic behavior of drilling mechanism effectively. In view of the coupling vibration and low drilling efficiency of auger drilling machine, a dynamic coupling model of multi-drilling mechanism was established to analyze the vibration characteristics under different coal hardness, drilling depths and rotating speeds. Simultaneously, the vibration tests of drilling process were conducted on the coal cutting test bed, and the results correspond with the simulation results. The results show that: the vibration displacement magnitude and fluctuation of multi-drilling mechanism increase with the coal hardness, while decrease then increase with the drilling depth, and increase then decrease with the rotating speed. The increases of coal hardness and drilling depth result in difficulty for coal cutting. The cutting torque decreases with rotating speed, while there is little influence on the feeding resistance

Micro and nano dual-scale structures fabricated by amplitude modulation in multi-beam laser interference lithography

© 2017 Optical Society of America. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reservedIn this work, an effective method was presented to obtain a specific micro and nano dual-structures by amplitude modulation in multi-beam laser interference lithography (LIL). Moiré effect was applied to generate the amplitude modulation. The specific intensity modulation patterns can be obtained by the control of the parameter settings of incident laser beams. Both the incident angle and azimuth angle asymmetric configurations can cause the amplitude modulation in the interference optic field and the modulation period is determined by the angle offset. A four-beam LIL system was set up to fabricate patterns on photoresist and verify the method. The experimental results are in good agreement with the theoretical analysis

Fast Fourier transport analysis of surface structures fabricated by laser interference lithography

This paper presents an FFT (fast Fourier transform) analytical method for the study of surface structures fabricated by laser interference lithography (LIL). In the work, the FFT analytical method combined with Gaussian fitting is used to determine the periods and pattern distributions of surface structures from frequency spectra. For LIL, the processing parameters of incident and azimuth angles can be obtained corresponding to the period and pattern distribution. This work facilitates the detection of micro- and nano-structures, the analysis of pattern distribution in engineering, and the processing error analysis of LIL

A Review of Fibre Reinforced Polymer (FRP) Reinforced Concrete Composite Column Members Modelling and Analysis Techniques

The use of fibre-reinforced polymer (FRP) to confine concrete columns improves the strength and ductility of the columns by reducing passive lateral confinement pressure. Many numerical and analytical formulations have been proposed in the literature to describe the compressive behaviour of FRP confined concrete under both monotonic and cyclic loads. However, the effect of a stress/strain level in the columns has not been well defined because of the lack of well-defined strategies of modelling and oversimplification of the model. This paper reviews the existing FRP combinations and the available numerical and analytical methods to determine the effectiveness of the adopted method. An effort has been made to examine the usage of FRP materials in column applications in existing building regimes and highlights the possible future scopes to improve the use of FRP confined concrete in civil applications

The Ninth Visual Object Tracking VOT2021 Challenge Results

acceptedVersionPeer reviewe

Analysis of three-intensity decoy-state phase-matching quantum key distribution

Phase-matching quantum key distribution (PM-QKD) protocol has been widely researched since it was proposed. This scheme is proven to beat the linear bound. In this paper, the performance of three-intensity decoy-state PM-QKD is discussed. The effects of various parameters on the performance of transmission system with statistical fluctuation and source error are analyzed by numerical simulation. The results show that the protocol has good performance. The effects of signal state intensity and decoy-state intensity on key rate are analyzed, and the optimal key rate and the intensity of signal and decoy states are given